Ranking System for NonDestructive Testing Devices
to Assess Quality of HMA
during Construction
Ahmed Faheem – Bloom Companies LLC
Dr. Robert Schmitt – UW Platteville
Dr. Imad Al-Qadi – UIUC
Goal

Investigation and Development of a NonDestructive System to Evaluate Critical
Properties of Asphalt Pavements during
the Compaction Process
Strategy

Define Critical Characteristics of
Compaction

Identify Non-Destructive Technologies

Rank Technologies on Technical Merits,
field, portability, training, cost, practicality
Project Stages

Stage 1:
◦ Determine critical properties
◦ Select promising non-destructive testing
technologies

Stage 2: Field data collection
◦ Select field compaction sites
◦ Collect data using proposed NDTs

Stage 3: Data Analysis
◦ Analyze data
◦ Evaluate quality of data collected from each
NDT
Background and Stage 1
Objective
•Non-destructive technologies are emerging
•Move beyond density and smoothness
•New measures for characterizing pavement
•Ability to assess entire pavement sections
•Real-time data retrieval
•Objective: Rank NDTs to guide agency
selection
Critical Characteristics

Survey of 12 states by Washington DOT
(1999)
Critical Characteristics and Impact
Agency-specific rank:
#1
#2
#3
Critical Properties
- Characteristics critical to
compaction from Lit.
- Agency-specific:
Search:
1.In-place
1.Mix segregation
compaction
2.In-place compaction
2.Temperature
3.Smoothness
segregation
4.Temperature segregation 3.Pavement modulus
5.Layer thickness
6.Layer bond
7.Pavement modulus
Non-Destructive Technologies:
Factors to Consider:

Operational principle
 Environmental
limitations

Measures and indicators


Test equipment
 Degree

Portability of the test

Cost

Complexity in the field

States using in practice

Time to conduct test
Reliability of collected data
of training required
Available Technologies 
Infrared Thermography


Washington, Texas
25-50°F corrective
action
> 50°F suspend, no
bonus
Thermal Segregation
$30,000
Intelligent Compactor


Index, CCV,
vibration
modulus,
stiffness
$175,000 to
$280,000 (25%
above base roller
price)
GPR



Thickness,
segregation,
delamination, ASTM
Dry pavement
$40,000 to $80,000
(minus vehicle)
Deflectometers





Deflection, stiffness, moduli
<140°F pavement
LWD no states spec for HMA
Layers only; highly variable
$17,000
Seismic
Average Modulus (ksi)
2500
2000
1500
1000
500
0
91
92
93
Density (%)




Seismic waves, moduli, PSPA portable, SPA
discontinued
Temperature dependent
No state specs, TxDOT design manual
$30,000
94
95
Permeameters





Water = NCAT
No ASTM or state
specs
Autocorrelation
(repeatability)
<140°F pavement
$800





Air = ROMUS
No ASTM or state
specs
More repeatable
<140°F pavement
$6,000
NDT vs. Critical Characteristics
Continuous
coverage?
Width
Mix
Seg.
Thermography
Yes, lane

IC
Yes, drum
GPR
Yes, 1 ft.
Deflectometer
No

PSPA
No

Permeameter
No
Nuclear/EM
No
Laser
Yes, 1 ft.
NDT
Com- Smoo- Temp.
paction thness Seg.
Thickness
Moduli



Bond








Agency Specific: Critical Characteristics
vs. NDT
NDT
Continuous
coverage?
Width
Rank
Compaction
Temp.
Seg.
Moduli
1
2
3

Thermography
Yes, lane
IC
Yes, drum

GPR
Yes, 1 ft.

Deflectometer
No

PSPA
No

Permeameter
No
Nuclear/EM
No
Laser
Yes, 1 ft.




Ranking System (Scoring)

7 Attributes:









Portability
Complexity
Time
Environmental Sensitivity
Reliability
Training
Price
4 levels:
Excellent(4), Good(3), Moderate(2), Poor(1)
Cumulative score is calculated
Levels of NDT Attributes
Level
Portability
Complexity
Reliability
Training
Excellent
Moves rapidly
Self-contained
Easy to operate
Highly accurate
Minimal training
Good
Moves rapidly
Attached to a
vehicle
Multiple steps are
required
Two or more
primary phases
Good accuracy
but requires
continuous
calibration
Multiple phases,
and steps within
each phase
Multiple steps
within phases
Knowledge of
calibration
Higher testing
variability with
known bias
Requires
continuous
calibration
Capability for
data collection
and statistical
analysis
Technology
considered at
experimental
phase
In-depth
understanding
of pavement
engineering
principles
Fair
Moves rapidly
Requires trailering
Poor
Requires multiple
Requires trailering
phases
Considerable set
Knowledge of
up time
sophisticated
equipment
Scoring
Score for
Equipment
Characteristics
(Cumulative)
x
Score for
Agency
Objectives
=
Overall
Score
Scoring Example for FWD
Objectives Score (Agency Specific):
4
3
2
1
=
=
=
=
Compaction
Thermal Seg.
Modulus
Other
FWD:
Objectives
2 = During Lay down
1 = After Compaction
Measures and
Indicators
Construction Process
Utilization
Modulus
After Compaction
2
1
Objectives Score = 3
Overall Score = 13 x 3 = 39
Ranking
Ranking Summary: Critical Characteristics
NDT
Continuous
coverage?
Width
ComTemp.
Moduli
paction Seg.


Overall
Score
IC
Yes, drum
Thermography
Yes, lane
GPR
Yes, 1 ft.
PSPA
No

80
LWD
No

68
Nuclear/EM**
No
FWD
No
Permeameter
No

120

110

85

105

39

34
Laser
Yes, 1 ft.
** Nuclear Gauges will be used in field for
comparison
30
Ranking, Vendors and Prices
Ranking
NDT
Vendor and Model
Price
($k)
1
Intelligent
Compaction
Sakai SW900 or
Bomag BW278AD-4
175-280
2
Infrared
Thermography
Moba Corporation
Pave-IR
28
3
GPR
GSSI RADAN
40-80
4
PSPA
Geomedia R&D
PSPA-PU
30
5
LWD
Zorn ZFG-2000A
17
What Next?
Stage 2
1. Field Testing (Completed)
 Stage 3
1. Analyze collected data.
2. Identify variability.
3. Validate GPR as surrogate density
measurement.
4. Identify mix design critical factors affecting
constructed quality.
 Final Report

Many Thanks !
Wisconsin Highway Research Program,
www.whrp.org
 Presentation may not reflect official views,
policies, standard specifications or
regulations of Wisconsin DOT or US DOT.

Vendors – MOBA, Sakai, GSSI, Geomedia
 Contractors – Mathy Construction, Payne
& Dolan

Thank You
Questions?
Contact: afaheem@bloomcos.com